I haven't seen any thread here that talks about Coco, so I might as well start one since I've just started growing with it and I'm loving the results!

I'm no expert, but I have tried to put together some of the hints and tips about using Coco that I have found on the interweb. Many thanks to C.E2 and Hundred Gram Oz for the main bulk of the information. If you find any missing or incorrect details please feel free to comment.

Coco is basically a buffered (be sure it is !), reusable* hydro medium and thus should be treated like a hydro medium, some like to call it 'semi-hydroponic' because it is more forgiving than full hydro. The thing is, you can water coco like you water soil, every day or 2 and you will get soil results but if you water coco a few times per day you will really reap the rewards of hydroponic results in a more stable medium. Therefore if used hydroponically, Coco will give you plants that grow bigger, better, and faster than in soil.

*: You can re-use a pH-buffered bag of coco for up to 4 times. After that you must use buffering agents and re-strengthen the coco with trace minerals or else you will run into lockout problems ! Also, if you plan to reuse (you should), be sure you apply enzyme products in the final weeks of the prior grow and first weeks of the subsequent one. Make sure you lightly sieve your coco to remove all roots you can find. The rest will be taken care of by the enzyme products.

Preparing:

Unless you are preparing coco in bulk, just take it out of the bag and pack it into your pots not too much, but not too little either as the coco will pack itself every time you water and you end up with coco a few inches under the rim of the pot, not good. I like to have the final level just a few centimetres (2-3) under.

6-6.5L are the smallest I'd recommend, after going through a nightmare with 3.5L pots (they get dry so damn fast).It might be good to mix some perlite in with the coco. Maybe 15-20%, I wouldn't recommend more as it will hurt the buffering strength of your medium. Some growers like to add hydroton at the base of the pots, this assists in drainage, some also add layer of hydroton at the top of the coco to help slow down evaporation.

Regardless of what is printed on the bag, it is always a good idea to water your medium thoroughly before use plant your seeds with low EC/ppm water, around 0.6-0.8EC, not higher, and pH around 5.7 (acidity encourages the root growth). I plant my seeds directly into the final pot as I don't really like transplanting in coco as coco is more fragile and will break up easy and mess up your roots. This is up to you though of course. Don't use plain water.... not even once.... as the buffering capacity of the medium will be wrecked.

Note: If you are going with cuts instead of seeds you can use higher ECs like 1.0, but really less is more at the beginning stage and low ECs help encourage the roots to grow rapidly into the medium to get more of the good stuff.

Watering:

I will talk about how wet the medium should be, as a lot of people get it wrong in the beginning. People like to say that you can't overwater in coco, I agree with them to a certain extent but you can overwater if you give them too much when they don't have a well developed root system, that's why it's important to harden off the roots and let them go hunting for nutrients at the beginning, this will help to build the root system. Once the root system is developed it is very very hard to overwater, they will take all you can throw at them and ask for more.

By the way, you can either water by hand like a normal soil grow or use a drip system, which is more preferable in coco for the later stages as it helps the wetness of the medium stay more stable than a hand watering schedule, which in turns keeps pH more stable and keeps the plants happier.

If you want to hand water make sure you water slowly as the coco medium is quite easy to dislodge. So if you water fast you will notice that your roots are floating ! Not good ! In both cases, you need around 20% runoff to keep your medium healthy. You cannot overwater coco, the more water you give, the better, you just waste water and nutes though.

During the first **two to three weeks, the coco medium should be treated somewhat more or less like soil though, not too wet, until the root system is fully established. It is recommended that you use rooting tonics like Canna Rhizotonic or H&G Roots Ecxellurator to get your plants to root up as fast as possible. Never let your coco dry though! Once the surface looks a bit flaky you need to water.

**: I want to make this point clear. It's not a matter of days or weeks. You need to wait until the root system looks established enough to start taking the full hydro experience It might take two, it might take five, depending on the condition of your medium, whether you use root boosters, and the general health of your plants and roots. As mentioned earlier the soil-like treatment for the first few weeks encourages the roots to dig deep and form up well.

Once your plant is all rooted up, you can, and should, keep your coco medium wet at all times, since the pH of the medium will change a bit as it gets drier, and even if the coco has pH buffering, that is best left to combat the pH fluctuation that occurs when the plant feeds and leeches ion from the medium. Within a week or two you will start to notice thick fuzzy white hydro roots shooting out.

Keeping the medium properly watered eventually gets harder and harder as the plants becomes big and start taking up quite a lot of water, and this is why a drip system is better as it helps keep the coco wet all the time. If you want to go with hand watering, you will probably need to water once a day starting from week 2-3, (once per 2-3 days prior to that), and probably up to 2-3 times a day. This will vary with how big your plant gets, how much the strain itself drinks, how much you ventilate, your RH, and temperatures, etc.

Once you water 3x per day your plants will start to grow super fast, FAT stalks, branching growing like crazy, it really is fun seeing the explosive growth rate. I feed 3 x per day right up until flower stretch is over then I bang up the waterings to 5x per day just as the buds switch into swelling mode, the plants react great. You see, when you feed a plant you aren't just giving it fresh nutrients, you are also giving fresh oxygen to the roots, the nutrient solution saturates the medium and pushes out the stale O2, as the solution works its way down the medium it draws in fresh oxygen from the top, this is one of the reasons why I think multi feeds works so well with coco. Your giving your plants access to more fresh oxygen.

Now one of the huge advantages to growing with coco DTW is the fact that you are watering to you get a little run off each time, which goes to a waste tray/rez to be dumped later. That little bit of run off ensures that each and every time you water your plants (3-5x per day) you're also washing away excess salts, salt build up can be a problem in coco and you often have to flush it out to get rid of all the excess salts. Once you get that little bit of waste run-off from each watering you are effectively flushing it out every time you water, this means that you don't have to do a manual flush until the end of flower when you do the 'final flush'.

If you don't already use it then I can highly recommend you check out a product from House & Garden called, Drip Clean, I'll not go into the science behind it because all that information is easily accessed on the internet but this product will ensure that excess salts are washed away, Drip Clean attracts salts and other build up, it helps to purge them from your medium, and it also does a great job keeping your drippers clear.

Feeding/Nutes:

[Please note that for EC readings, I use a tap water of EC 0.2 as a base]You can use any chemical fertilizer on coco, but the ones produced specifically for it are best since the ratio of minerals and trace-minerals reflect what should be present in a coco medium. Also, they include buffering agents that help the coco stabilize the pH at 5.5-6.0, and are also made to be best absorbed in that spectrum.

It is very important to feed with every watering in coco. Even from day 0. A totally nuteless medium will discourage roots from growing rapidly and ruin the pH buffering capacity, so start with 0.5-0.6EC for the first week, and I recommend you use products like rhizotonic as they really help in coco.

By the end of week 1, or around day 10, you should be upping your EC to around 0.8-1.0 already. The plants themselves will let you know once they need more. After the end of week 2 start increasing your EC by 0.1 each 5 days or week, depending on your plants. I would go to a maximum of 1.2-1.4 in veg, 1.4-1.8 in flower. This changes with strains as some need more and some need less.

**Note: I no longer use additional PK during flower, nor do I recommend it. Instead, I use a 3-part nute system and I increase/decrease the pk ratio at will by using different ratios of the grow/micro/bloom bottles.(**)If you use PK13/14 or any pk cocktail take your EC down to 1.6 or so first since even 1.8 will sometimes burn your plants with those kinds of products. Take it up slowly to see how much your plants can take and try not to burn your tips ! Use the same dose for a few days as sometimes a dose that works for one day will burn your plants after consecutive waterings.

Also, to know how much PK 13/14 to apply, here is what I do, as I never follow bottle labels. Say at week 3-4 of flower you are gonna start giving PK 13/14. At the first day if say your EC should have been 1.7, mix you base nutes to 1.6, and add PK 13/14 till it reaches 1.7. And of course regulate pH as pk13/14 will raise it. Each week decrease your base A/B or 1-component nutes EC by 0.1 and up the PK 13/14 by 0.1.

This will gradually make your N go down and you PK go up in the mix, as you better decrease the N later on in flower so as to decrease the leafiness. Especially in autos since its needed. You MAY need to add some trace minerals and/or cal/mag when you do this. Some bloom additives take this into consideration and have trace minerals and cal mag inside of them along with the hormones and other plant cocktails. Again, take it slow and make the transition in small steps and as to not shock your roots/plants.

This needs some trial-n-error to dial in but by starting low and working your way up you can pretty much nail it from the first try or two. Don't be discouraged to try different mixes on differents plants to see what works best for you.I take my EC down to 1.6 one week before the flush.

Note: You can follow your nutrient supplier's grow schedule, but most of them recommend EC's that are too high and dosages that will totally fry your plants. I always start with 1/4 the dosage that the bottle say and look at EC to measure the dosage, not how much ml per L of nutrient.

If they are green and going dark, you can probably pull back the EC. If they are going a bit light green, up your EC. Don't wait for them to go yellow ! And try not to burn the tips !

This takes some time to get used to and this varies from strain to strain.Keep in mind that autoflowers generally tolerate less EC than photoperiod strains, and different autoflower strains have different EC requirements. This of course goes for all mediums, not just coco.

Flushing

This is still a debated topic amongst coco growers. Some people do it and some don't. If you want to though, only do it for the last 5-10(****) days of your grow in hydro/coco. And preferably give the plants a dark period during the flush as many report this helps the plant eat everything and pump out as much resin as possible.

****: I've done tests with 5 days and 10 days. I see no difference but some people just insist on flushing for 2 weeks or so in coco. To each his own.

Cheers Bro, what I like about it is that you start on EC0.7 instead of piddling around with EC0.3, and the fact that I can over water them without any fear of drowning them, in fact they love it because you give the roots extra oxygen each time you feed them.